Photostabilizers, UV absorbers, and methods of photostabilizing a sunscreen composition

ABSTRACT

Derivatives of fluorene, including ester derivatives of cyano(9H-fluoren-9-ylidene) acetic acid, and sunscreen compositions including a mixture of a photoactive compound and an ester derivative of cyano(9H-fluoren-9-ylidene) acetic acid are disclosed herein. Also disclosed are methods for terminating a polymer chain with an ester derivative of cyano(9H-fluoren-9-ylidene) acetic acid and methods of filtering out ultra-violet light from a substrate by the use of one or more such derivatives.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of U.S. patent application Ser. No.10/246,434, filed Sep. 17, 2002.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to compounds and methods to increase thephotostability of a sunscreen composition. Moreover, the inventionrelates to photostable sunscreen compositions and a new class ofphotoactive compounds. More particularly, the invention relates to theuse of derivatives of diphenylmethylenemalonic acid and derivatives offluorene, including derivatives of cyano(9H-fluoren-9-ylidene) aceticacid and diesters and polyesters of 9H-fluoren-9-ylidenemalonic acid tophotostabilize a sunscreen composition.

Brief Description of Related Technology

It is well known that ultraviolet radiation (light) having a wavelengthfrom about 280 nm or 290 nm to about 320 nm (UV-B) is harmful to humanskin, causing bums that are detrimental to the development of a good suntan. UV-A radiation (about 320 nm to about 400 nm), while producingtanning of the skin, also can cause damage, particularly to verylightly-colored or sensitive skin, leading to reduction of skinelasticity and wrinkles. Therefore, a sunscreen composition for use onhuman skin preferably includes both a UV-A and a UV-B filter to preventmost of the sunlight within the full range of about 280 nm or 290 nm toabout 400 nm from damaging human skin.

Ultraviolet radiation from the sun or artificial sources can also causeharm to coatings containing photoactive substances, such as photoactivepigments and dyes, by breaking down chemical bonds in the structure of acomponent such as a polymer, a pigment, or a dye. This photodegradationcan lead to color fading, loss of gloss, and loss of physical andprotective properties of a coating. Photodegradation can take place inseveral steps which include one or more components of a coatingabsorbing UV radiation. The absorbed radiation can excite the absorbingmolecules and raise them to a higher energy level, which can be veryreactive. If the molecule cannot be relaxed, bond cleavage and theformation of free radicals will occur. These free radicals can attackone or more color molecules and/or a polymer backbone and form more freeradicals. UV-A and UV-B filters can also be used to absorb UV radiationto protect a pigmented coating.

The UV-B filters that are most widely used in the U.S. in commercialsunscreen compositions are paramethoxycinnamic acid esters, such as2-ethylhexyl paramethoxycinnamate, commonly referred to as octylmethoxycinnamate or PARSOL MCX, octyl salicylate, and oxybenzone.

The organic UV-A filters most commonly used in commercial sunscreencompositions are the dibenzoylmethane derivatives, particularly4-(1,1-dimethylethyl)-4′-methoxydibenzoylmethane (also calledavobenzone, sold under the brand name PARSOL 1789). Otherdibenzoylmethane derivatives described as UV-A filters are disclosed inU.S. Pat. Nos. 4,489,057, 4,387,089 and 4,562,067, the disclosures ofwhich are hereby incorporated herein by reference. It is also well knownthat the above described UV-A filters, particularly the dibenzoylmethanederivatives, can suffer from rapid photochemical degradation, when usedalone or when combined with the above-described most commercially usedUV-B filters.

Typically, the above-described UV-B filters are combined with the abovedescribed UV-A filters in a solution with other lipophilic or oilyingredients. This solution of oily ingredients, known to formulators ofcosmetic products including sunscreens as the “oil phase,” is typically,but not necessarily, dispersed with the help of emulsifiers andstabilizers into an aqueous solution composed primarily of water, tomake an emulsion which becomes a final cream or lotion form of asunscreen composition.

The performance of a photoactive compound or a combination ofphotoactive compounds in a sunscreen composition has been extremelydifficult to predict based on the levels of photoactive compounds in theformulation, particularly when the formulation includes one or morephotoactive compounds that suffer from relatively rapidphotodegradation, such as avobenzone. Because of this, each formulationhas required expensive laboratory testing to determine the UVabsorbance, as a function of time (quantity) of exposure of theformulation to UV radiation. Moreover, a particularly difficult problemis presented when one photoactive compound in a sunscreen compositionacts to increase the rate of photodegradation of another photoactivecompound in the composition. This can be accomplished in a number orways, including a bimolecular reaction between two photoactive compoundsand a lowering of the threshold energy need to raise a photoactivecompound to its excited state. For example, when avobenzone is combinedwith octyl methoxycinnamate a bimolecular pathway leads to the rapidphotodegradation of both the dibenzoylmethane derivative and the octylmethoxycinnamate.

Methods and compositions for stabilizing photoactive compounds, such asdibenzoylmethane derivatives with the use of diesters and/or apolyesters of naphthalene dicarboxylic acid are described in U.S. Pat.Nos. 5,993,789, and 6,284,916, the disclosures of which are herebyincorporated herein by reference. Other methods of stabilizing adibenzoylmethane derivative include the addition of anα-cyano-β,β-diphenylacrylate compound to a sunscreen compositionincluding a dibenzoylmethane derivative. See, Deflandre et al, U.S. Pat.No. 5,576,354 and Gonzenbach et al., U.S. Pat. No. 6,033,649.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of the absorbance of octocrylene(2-ethylhexyl-2-cyano-3,3 diphenylacrylate) and octofluorene(2-ethylhexyl cyano(9H-fluoren-9-ylidene) acetate) from a wavelength of250 nm to 400 nm, and at a concentration of 10 ppm (parts per million)in cyclohexane.

FIG. 2 is a graph of the percent of the original absorbance of sunscreencompositions including 4% by weight of octyl-p-methoxycinnamate and 2%by weight of avobenzone at a wavelength of 370 nm, at variousconcentrations of octofluorene after the compositions have been exposedto 35 minimal erythemal dose (MED)units, wherein 1 MED is 21 millijoulesper square centimeter (mJ/cm2).

FIG. 3 is a graph of the percent of the original absorbance of sunscreencompositions including various amounts of octocrylene and octofluorene.The octocrylene and octofluorene were prepared in sunscreen compositionsincluding 7.5% by weight of octyl-p-methoxycinnamate, 5% by weight ofoctyl salicylate and 2% by weight of avobenzone, wherein the percentabsorbance is measured at a wavelength of 370 nm and at variousintervals of exposure to radiation up to and including 35 MED.

FIG. 4 is a graph of the percent of the original absorbance of sunscreencompositions including octocrylene and octofluorene at variousconcentrations in sunscreen compositions including 4% by weight ofoctyl-p-methoxycinnamate and 2% by weight of avobenzone, wherein thepercent absorbance is measured at a wavelength of 310 nm and at variousintervals of exposure to radiation, up to and including 35 MED.

FIG. 5 is a graph of the percent of the original absorbance ofcompositions including octocrylene and octofluorene at variousconcentrations in sunscreen compositions including 4% by weight ofoctyl-p-methoxycinnamate and 2% by weight of avobenzone, wherein thepercent absorbance is measured at a wavelength of 370 nm and at variousintervals of exposure to radiation, up to and including 35 MED units.

FIG. 6 is a graph of the percent of the original absorbance of thesunscreen compositions listed in Table II, wherein the percentabsorbance is measured at a wavelength of 370 nm and at variousintervals of exposure to radiation, up to and including 30 MED.

FIG. 7 is a graph of the percent of the original absorbance ofcompositions including octofluorene, octocrylene,diethylhexyl-2,6-naphthalate (DEHN) in a composition including 5% byweight of octyl salicylate and 2% by weight of avobenzone wherein highlypolar solvent were included in the oil-phase of the composition to raisethe dielectric constant of the oil-phase, and the percent absorbance ismeasured at a wavelength of 370 nm and at various intervals of exposureto radiation, up to and including 30 MED.

FIG. 8 is a graph of the percent of the original absorbance of thesunscreen compositions listed in Table VII, wherein the percentabsorbance is measured at a wavelength of 370 nm and at variousintervals of exposure to radiation, up to and including 30 MED.

SUMMARY

One aspect of the invention is a composition including a mixture of aphotoactive compound and a compound selected from the group of compoundsincluding derivatives of diphenylmethylenemalonic acid and derivativesof fluorene (e.g., derivatives of cyano(9H-fluoren-9-ylidene) aceticacid, and diesters and polyesters of 9H-fluoren-9-ylidenemalonic acid).

Another aspect of the invention includes derivatives ofcyano(9H-fluoren-9-ylidene) acetic acid.

Still another aspect of the invention is a diester and/or a polyester ofdiphenylmethylenemalonic acid.

Yet another aspect of the invention is a method for stabilizing asunscreen composition including a photoactive compound by the additionof a derivative of 9-methylene-9H-fluorene.

Still another aspect of the invention is a method for stabilizing asunscreen composition including a photoactive compound by the additionof a diester or a polyester of diphenylmethylenemalonic acid.

Still another aspect of the invention is method of filtering outultra-violet light by the use of a derivative of9-methylene-9H-fluorene.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Sunscreen compositions containing one or more of a photoactive compound,such as a dibenzoylmethane derivative UV-A filter compound, and aderivative of 9-methylene-9H-fluorene and/or diesters ofdiphenylmethylene malonic acid are described herein. One aspect of thesunscreen compositions described herein are methods of photostabilizinga sunscreen composition including a dibenzoylmethane derivative, such as4-(1,1-dimethylethyl)-4′-methoxydibenzoylmethane (PARSOL® 1789), whereinone or more photoactive compounds present in a sunscreen composition(e.g., avobenzone) are made more photostable by the addition of aderivative of diphenylmethylenemalonic acid and/or a derivative offluorene, including a derivative of cyano(9H-fluoren-9-ylidene) aceticacid and diesters and polyesters of 9H-fluoren-9-ylidenemalonic acid.Also disclosed herein are methods for filtering out ultra-violet lightfrom human skin including the step of applying a derivative ofcyano(9H-fluoren-9-ylidene) acetic acid to the skin.

A photoactive compound can be considered stable when, for example, after30 MED irradiation the photoactive compound has retained at least about90% of its original absorbance at a wavelength or a range of wavelengthsof interest (e.g., the wavelength at which or near a photoactivecompound has a peak absorbance, such as 350-370 nm for avobenzone).Likewise, a sunscreen composition can include a plurality of photoactivecompounds and a sunscreen composition, as a whole, can be consideredstable when, for example, after 30 MED irradiation the sunscreencomposition has retained at least about 90% of its original absorbanceat one or more wavelengths of interest (e.g., at or near the peakabsorbance wavelength of the primary photoactive compounds).

It has surprisingly been found that the addition of one or more of aderivative of diphenylmethylenemalonic acid and a derivative of fluorene(including a derivative of cyano(9H-fluoren-9-ylidene) acetic acid anddiesters and polyesters of 9H-fluoren-9-ylidenemalonic acid) to asunscreen composition including a diester or polyester of naphthalenedicarboxylic acid can significantly increase the photostability of thesunscreen composition and/or photounstable components present therein.Without intending to be limited to any particular mechanism of achievingthis increase in stability, it is believed that a diester or polyesterof naphthalene dicarboxylic acid stabilizes a dibenzoylmethanederivative by accepting the triplet energy of the dibenzoylmethanederivative once the dibenzoylmethane derivative has reached an excitedstate as a result of the absorption of ultra-violet light. Once adibenzoylmethane derivative is excited, it is prone to degrade accordingto a number of pathways; however, the degradation of thedibenzoylmethane derivative can be substantially reduced or prevented bythe use of a diester or polyester of naphthalene dicarboxylic acid toquench (accept) the triplet excited state energy present in an exciteddibenzoylmethane molecule. Thus, in one pathway of degradation, adibenzoylmethane derivative is excited to its triplet state and theexcited state triplet energy is released in a bond breaking step,thereby preventing the dibenzoylmethane derivative from furtheraccepting ultra-violet radiation. A diester or polyester of naphthalenedicarboxylic acid may stabilize a dibenzoylmethane derivative byaccepting the triplet state (excited state) energy of the exciteddibenzoylmethane derivative in such a way as to convert the exciteddibenzoylmethane derivative back to a ground state that is capable ofreaccepting ultra-violet radiation (energy transfer).

For this process to work continuously, the diester or polyester ofnaphthalene dicarboxylic acid must transfer or convert the energy thatwas accepted from the excited dibenzoylmethane derivative. Withoutintending to be limited to a particular mechanism, it is believed thatwhen a diester or polyester of naphthalene dicarboxylic acid is excitedto its triplet state it dissipates the triplet excited state energythrough vibrations (e.g., as heat), which in this group of molecules isa relatively slow mode of dissipating energy. It has been found, quitesurprisingly, that by the addition of even low levels (e.g., less than1% by weight) or very low levels (e.g., 0.5% by weight or less) of aderivative of fluorene (e.g., a derivative ofcyano(9H-fluoren-9-ylidene) acetic acid and a diester and/or a polyesterof 9H-fluoren-9-ylidenemalonic acid), such a compound is able to accepttriplet excited state energy from an excited diester or polyester ofnaphthalene dicarboxylic acid. Thus, according to one possiblemechanism, the efficiency of the dissipation of the excited state energyin an excited diester or polyester of naphthalene dicarboxylic acid isgreatly improved by a transfer of energy from an excited diester orpolyester of naphthalene dicarboxylic acid to a derivative of fluorene(e.g., a derivative of cyano(9H-fluoren-9-ylidene) acetic acid and adiester and/or a polyester of 9H-fluoren-9-ylidenemalonic acid).

Thus, preferably, a sunscreen composition disclosed herein includes adiester or polyester of naphthalene dicarboxylic acid selected from thegroup consisting of compounds of formulae (VII) and (VIII), andcombinations thereof:

wherein R¹³ and R¹⁴ are the same or different and are selected from thegroup consisting of C₁-C₂₂ alkyl groups, diols having the structureHO—R¹⁵—OH, and polyglycols having the structure HO—R¹⁶—(—O—R¹⁵—)_(n)—OH;wherein each R¹⁵ and R¹⁶ is the same or different and selected from thegroup consisting of C₁-C₆ straight or branched chain alkyl groups; andwherein m and n are each in a range of 1 to 100 and p is in a range of 0to 100. Preferably, a sunscreen composition includes a diester offormula (VIII) wherein R¹ and R² are 2-ethylhexane and p is 0.

A sunscreen composition disclosed herein can be combined into acosmetically acceptable carrier, optionally including emollients,stabilizers, emulsifiers, such as those known in the art, andcombinations thereof. These additives can be used in preparing anemulsion from an aqueous system and a mixture of a filter system thatincludes one or more photoactive compounds and a solvent system thatincludes one or more organic solvents. When made, preferably theemulsion is an oil-in-water emulsion, wherein the oil phase is primarilyformed from a mixture of the filter system and solvent system.

A typical sunscreen composition includes one or more photoactivecompounds, wherein a photoactive compound acts to absorb UV radiationand thereby protect the substrate (e.g., human skin) from the harmfuleffects of UV radiation. The absorption process causes a photoactivecompound to reach an excited state, wherein the excited state ischaracterized by the presence of excited energy (e.g., singlet energy ortriplet energy), as compared to the ground state of the photoactivecompound. Once a photoactive compound reaches an excited state thereexists a number of pathways by which the excited photoactive compoundcan dissipate its excess energy (e.g., triplet energy), however, many ofthose pathways adversely affect the ability of the photoactive compoundto further absorb UV radiation.

It has surprisingly been found that the addition of one or more of aderivative of diphenylmethylenemalonic acid and a derivative of fluorene(including derivative of cyano(9H-fluoren-9-ylidene) acetic acid anddiesters and polyesters of 9H-fluoren-9-ylidenemalonic acid) increasesthe photostability of a sunscreen composition. Without intending to belimited to any particular mechanism by which a such compounds are ableto quench (accept the excited state energy) an excited photoactivecompound, it is believed that, for example a 9-methylene-9H-fluorenederivative accepts the excited state energy and dissipates the energykinetically in the form of rapid isomerizations. An example of thisprocess is shown below:

wherein the 9-methylene-9H-fluorene derivative (2-ethylhexylcyano(9H-fluoren-9-ylidene) acetate, shown above as A and hereinafterreferred to as octofluorene), accepts the triplet excited state energyand forms a diradical (shown above as A*) at the α and β positions ofthe acrylate, which converts the double bond into a single bond andallows for free rotation about the single bond. This rotation occursrapidly and efficiently to dissipate excited state energy accepted by aderivative of fluorene.

Commonly-assigned U.S. patent application Ser. Nos. 10/092,131, now U.S.Pat. No. 6,537,529, and Ser. No. 10/092,132, now U.S. Pat. No.6,485,713, the disclosures of which are hereby incorporated herein byreference, describe compositions and methods for increasing thestability of photoactive compounds in a sunscreen composition, e.g., bythe addition of polar solvents to the oil phase of a composition. It hasbeen found, quite surprisingly, that by increasing the polarity of theoil phase of a sunscreen composition including one or more of aderivative of diphenylmethylenemalonic acid and a derivative offluorene, the stability of the sunscreen composition is increased. Nowknowing that the polarity of the solution affects the stability, onemight expect that the more polar the solution is, the greater thestability it will impart to the photoactive compound. In contrast, andeven more surprisingly, it has been found that as the polarity of asolvent system including a dissolved, rapidly photodegradable compoundis increased, the rate of photodecay initially decreases but thenincreases again as the polarity is further increased. Thus, aphotodegradable compound in solution will degrade as a second-orderfunction of the overall polarity of the solution. Currently acceptedphotochemical theory provides the possibility that the mechanism bywhich a photodegradable compound is stabilized is the transfer of aphotonically-excited electron to a nearby molecule of the same ordifferent species (see, e.g., N. J. Turro, Modern MolecularPhotochemistry, Chapter 9, Benjamin/Cummings Publ. Co., Menlo Park,Calif. (1991)), however photochemical theory does not describe theobserved phenomena. Though not intending to be bound by such a belief,the observed phenomena are believed to coincide with the electrontransfer theory of Professor Rudolph A. Marcus of the CaliforniaInstitute of Technology, for which he received the 1992 Nobel Prize inChemistry.

The dielectric constant of a solvent system is a preferred measure ofpolarity of a solvent system, for example because the dielectricconstant is a measure of both inherent and inducible dipole moments.Other measures of polarity include, but are not limited to, the inducedand/or inherent (permanent) dipole moment (e.g., in Debye units), theDimroth-Reichardt E_(T) parameter, and ionizing power. See generally, C.Reichardt, “Solvents and Solvent Effects in Organic Chemistry” 2nd ed.,Chap. 7: Empirical Parameters of Solvent Polarity, VCH Publishers, NewYork, N.Y, (1988). Moreover, a more detailed description of thesemethods of measuring the polarity of the compound or a series ofcompounds can be found in commonly assigned U.S. patent application Ser.Nos. 10/092,131 and 10/092,132.

Mathematically, photodegradation can be described by an exponentialfunction. Thus, Q(a), the absorbance after a radiation dose (i.e.,exposure to a quantity of radiation), can be described by the generalequation (i),

 Q(a)=Ae ^(−kr)  (i)

wherein A is the original (pre-exposure) absorbance, e is the naturallogarithm base, k is the rate constant of the photodecay, and r is thecumulative dose (e.g., in MED units). Because the absorbance decreasesas the cumulative dose increases (photodecay), the overall term −k willbe negative, and the greater the value of −k (i.e., closer to zero) and,thus, the lower the rate constant of photodecay, the lower is the rateof photodecay. For example, when Q(a) is plotted on a log scale versus ron a linear scale, the function forms a straight line with a slope equalto −k.

Furthermore, it has been found that, for a set of photoactive compoundsthat includes a photodegradable compound (e.g. avobenzone), the rateconstant of photodecay of the set of photoactive compounds can bedescribed as a second-order function of the polarity, preferably thedielectric constant (i.e., relative permittivity) of the filter setdissolved in the solvent system. Thus, for example, the rate constant ofphotodecay of a filter set that include one or more of a photoactivecompound, can be described by the general equation (ii),k=−(xε ² +yε+z)  (ii)wherein x, y, and z can be empirically determined. The dielectricconstant at the theoretical minimum rate constant of photodecay −k mindescribed by formula (iii), $\begin{matrix}{ɛ_{k\quad\min} = \frac{- y}{2x}} & ({iii})\end{matrix}$wherein x and y are defined as above.

The phenomena described above, coupled with the knowledge that,heretofore, sunscreen compositions have been formulated without specificregard to. the relationship between polarity and photostability and, innewly-discovered fact, have had non-optimal polarities, forms the basisfor at least one aspect of the compositions and methods describedherein.

In a sunscreen disclosed herein, preferably, one or more of a highlypolar solvent is present in the oil-phase of the composition.Preferably, a sufficient amount of a polar solvent is present in asunscreen composition to raise the dielectric constant of the oil-phaseof the composition to a dielectric constant of at least about 7,preferably at least about 8.

A photoactive compound is one that responds to light photoelectrically.In the compositions disclosed herein, a photoactive compound is one thatresponds to UV radiation photoelectrically. For example, photoactivecompounds that respond to UV radiation photoelectrically by rapidphotodegradation can benefit highly from the compositions and methodsdisclosed herein, even though the benefits of the compositions andmethods disclosed herein are not limited to such compounds.Photostability is a potential problem with all UV filters because theyare deliberately selected as UV-absorbing molecules. In otherapplications, a photoactive compound may be a pigment or a dye (e.g., ahydrophobic dye).

UV filters include compounds selected from the following categories(with specific examples) including: p-aminobenzoic acid, its salts andits derivatives (ethyl, isobutyl, glyceryl esters;p-dimethylaminobenzoic acid); anthranilates (o-aminobenzoates; methyl,menthyl, phenyl, benzyl, phenylethyl, linalyl, terpinyl, andcyclohexenyl esters); salicylates (octyl, amyl, phenyl, benzyl, menthyl(homosalate), glyceryl, and dipropyleneglycol esters); cinnamic acidderivatives (menthyl and benzyl esters, alpha-phenyl cinnamonitrile;butyl cinnamoyl pyruvate); dihydroxycinnamic acid derivatives(umbelliferone, methylumbelliferone, methylaceto-umbelliferone); camphorderivatives (3-benzylidene, 4-methylbenzylidene, polyacrylamidomethylbenzylidene, benzalkonium methosulfate, benzylidene camphor sulfonicacid, and terephthalylidene dicamphor sulfonic acid); trihydroxycinnamicacid derivatives (esculetin, methylesculetin, daphnetin, and theglucosides, esculin and daphnin); hydrocarbons (diphenylbutadiene,stilbene); dibenzalacetone; benzalacetophenone; naphtholsulfonates(sodium salts of 2-naphthol-3,6-disulfonic and of2-naphthol-6,8-disulfonic acids); dihydroxy-naphthoic acid and itssalts; o- and p-hydroxydiphenyldisulfonates; coumarin derivatives(7-hydroxy, 7-methyl, 3-phenyl); diazoles (2-acetyl-3-bromoindazole,phenyl benzoxazole, methyl naphthoxazole, various aryl benzothiazoles);quinine salts (bisulfate, sulfate, chloride, oleate, and tannate);quinoline derivatives (8-hydroxyquinoline salts, 2-phenylquinoline);hydroxy- or methoxy-substituted benzophenones; uric acid derivatives;vilouric acid derivatives; tannic acid and its derivatives;hydroquinone; and benzophenones (oxybenzone, sulisobenzone,dioxybenzone, benzoresorcinol, 2,2′,4,4′-tetrahydroxybenzophenone,2,2′-dihydroxy-4,4′-dimethoxybenzophenone, octabenzone,4-isopropyldibenzoylmethane, butylmethoxydibenzoylmethane, etocrylene,and 4-isopropyl-dibenzoylmethane).

Particularly useful are: 2-ethylhexyl p-methoxycinnamate, 4,4′-t-butylmethoxydibenzoylmethane, 2-hydroxy-4-methoxybenzophenone, octyldimethylp-aminobenzoic acid, digalloyltrioleate,2,2-dihydroxy-4-methoxybenzophenone, ethyl4-[bis(hydroxypropyl)]aminobenzoate,2-ethylhexyl-2-cyano-3,3-diphenylacrylate, 2-ethylhexylsalicylate,glycerol p-aminobenzoate, 3,3,5-trimethylcyclohexylsalicylate,methylanthranilate, p-dimethylaminobenzoic acid or aminobenzoate,2-ethylhexyl p-dimethylaminobenzoate, 2-phenylbenzimidazole-5-sulfonicacid, 2-(p-dimethylaminophenyl-5-sulfoniobenzoxazoic acid, andcombinations thereof.

For a product marketed in the United States, preferredcosmetically-acceptable photoactive compounds and concentrations(reported as a percentage by weight of the total cosmetic sunscreencomposition) include: aminobenzoic acid (also called para-aminobenzoicacid and PABA; 15% or less), avobenzone (also called butyl methoxydibenzoylmethane; 3% or less), cinoxate (also called 2-ethoxyethylp-methoxycinnamate; 3% or less), dioxybenzone (also calledbenzophenone-8; 3% or less), homosalate (15% or less), menthylanthranilate (also called menthyl 2-aminobenzoate; 5% or less),octocrylene (also called 2-ethylhexyl-2-cyano-3,3 diphenylacrylate; 10%or less), octyl methoxycinnamate (7.5% or less), octyl salicylate (alsocalled 2-ethylhexyl salicylate; 5% or less), oxybenzone (also calledbenzophenone-3; 6% or less), padimate O (also called octyl dimethylPABA; 8% or less), phenylbenzimidazole sulfonic acid (water soluble; 4%or less), sulisobenzone (also called benzophenone-4; 10% or less),titanium dioxide (25% or less), trolamine salicylate (also calledtriethanolamine salicylate; 12% or less), and zinc oxide (25% or less).

Other preferred cosmetically-acceptable photoactive compounds andpreferred concentrations (percent by weight of the total cosmeticsunscreen composition) include diethanolamine methoxycinnamate (10% orless), ethyl-[bis(hydroxypropyl)]aminobenzoate (5% or less), glycerylaminobenzoate (3% or less), 4-isopropyl dibenzoylmethane (5% or less),4-methylbenzylidene camphor (6% or less), terephthalylidene dicamphorsulfonic acid (10% or less), and sulisobenzone (also calledbenzophenone-4, 10% or less).

For a product marketed in the European Union, preferredcosmetically-acceptable photoactive compounds and preferredconcentrations (reported as a percentage by weight of the total cosmeticsunscreen composition) include: PABA (5% or less), camphor benzalkoniummethosulfate (6% or less), homosalate (10% or less), benzophenone-3 (10%or less), phenylbenzimidazole sulfonic acid (8% or less, expressed asacid), terephthalidene dicamphor sulfonic acid (10% or less, expressedas acid), butyl methoxydibenzoylmethane (5% or less), benzylidenecamphor sulfonic acid (6% or less, expressed as acid), octocrylene (10%or less, expressed as acid), polyacrylamidomethyl benzylidene camphor(6% or less), ethylhexyl methoxycinnamate (10% or less), PEG-25 PABA(10% or less), isoamyl p-methoxycinnamate (10% or less), ethylhexyltriazone (5% or less), drometrizole trielloxane (15% or less),diethylhexyl butamido triazone (10% or less), 4-methylbenzylidenecamphor (4% or less), 3-benzylidene camphor (2% or less), ethylhexylsalicylate (5% or less), ethylhexyl dimethyl PABA (8% or less),benzophenone-4 (5%, expressed as acid), methylene bis-benztriazolyltetramethylbutylphenol (10% or less), disodium phenyl dibenzimidazoletetrasulfonate (10% or less, expressed as acid), bis-ethylhexyloxyphenolmethoxyphenol triazine (10% or less), methylene bisbenzotriazolyltetramethylbutylphenol (10% or less, also called TINOSORB M), andbisethylhexyloxyphenol methoxyphenyl triazine.(10% or less, also calledTINOSORB S).

All of the above-described UV filters are commercially available. Forexample, suitable commercially-available organic UV filters areidentified by trade name and supplier in Table I below:

TABLE I CTFA Name Trade Name Supplier benzophenone-3 UVINULM-40 BASFChemical Co. benzophenone-4 UVINUL MS-40 BASF Chemical Co.benzophenone-8 SPECTRA-SORB American Cyanamid UV-24 DEA-methoxycinnamateBERNEL HYDRO Bernel Chemical ethyl dihydroxypropyl-PABA AMERSCREEN PAmerchol Corp. glyceryl PABA NIPA G.M.P.A. Nipa Labs. homosalateKEMESTER HMS Humko Chemical methyl anthranilate SUNAROME UVA FeltonWorldwide octocrylene UVINUL N-539 BASF Chemical Co. octyl dimethyl PABAAMERSCOL Amerchol Corp. octyl methoxycinnamate PARSOL MCX BernelChemical PABA PABA National Starch 2-phenylbenzimidazole-5- EUSOLEX 6300EM Industries sulphonic acid TEA salicylate SUNAROME W Felton Worldwide2-(4- EUSOLEX 6300 EM Industries methylbenzildene)-camphorbenzophenone-1 UVINUL 400 BASF Chemical Co. benzophenone-2 UVINUL D-50BASF Chemical Co. benzophenone-6 UVINUL D-49 BASF Chemical Co.benzophenone-12 UVINUL 408 BASF Chemical Co. 4-isopropyl dibenzoylEUSOLEX 8020 EM Industries methane butyl methoxy dibenzoyl PARSOL 1789Givaudan Corp. methane etocrylene UVINUL N-35 BASF Chemical Co.methylene bisbenzotriazolyl TINOSORB M Ciba Specialtytetramethylbutylphenol Chemicals bisethylhexyloxyphenol TINOSORB S CibaSpecialty methoxyphenyl triazine. Chemicals

The term “alkyl” as used herein refers to straight- and branched-chainhydrocarbon groups, preferably containing one to thirty carbon atoms.Examples of alkyl groups are C₁-C₄ alkyl groups. As used herein thedesignation C_(x)-C_(y), wherein x and y are integers, denotes a grouphaving from x to y carbon atoms, e.g., a C₁-C₄ alkyl group is an alkylgroup having one to four carbon atoms. The term alkyl also includesvariations of an alkyl group including, an alkene (containing a doublebond) and an alkyene group (containing a triple bond). Nonlimitingexamples of alkyl groups include, methyl, ethyl, n-propyl, isopropyl,n-butyl, sec-butyl (2-methylpropyl), and t-butyl (1,1-dimethylethyl).

The term “hydroxy” as used herein refers to an “—OH” group.

The term “cycloalkyl” as used herein refers to an aliphatic cyclichydrocarbon group, preferably containing three to eight carbon atoms.Nonlimiting examples of cycloalkyl groups include cyclopropyl,cyclobutyl, cyclopentyl, and cyclohexyl.

The terms “substituted alkyl” and “substituted cycloalkyl” as usedherein refer to an alkyl or cycloalkyl groups having one or moresubstituents. The substituents can include, but are not limited to, oneor more of C₃-C₈ cycloalkyl, hydroxyalkyl, substituted cycloalkyl,ester, ether, aryl, heteroaryl, heterocycloalkyl, substituted aryl,substituted heteroaryl, substituted heterocycloalkyl, hydroxyl, halogen,cyano, amide, imide, urethane, and amino. The preferred substitutedalkyl groups have one to twenty carbon atoms, not including carbon atomsof the substituent group. Preferably, a substituted alkyl group is mono-or di-substituted at one, two, or three carbon atoms. The substituentscan be bound to the same carbon or different carbon atoms.

The term “ester” as used herein refers to a group of the generalformula:

wherein R is an alkyl group, cycloalkyl group, substituted alkyl group,or a substituted cycloalkyl group.

The term “amide” as used herein refers to a group of the generalformula:

wherein R is a hydrogen, alkyl group, cycloalkyl group, substitutedalkyl group, or a substituted cycloalkyl group.

The term “imide” as used herein refers to a group of the generalformula:

wherein R, R¹, and R² are each independently selected from alkyl groups,cycloalkyl groups, substituted alkyl groups, and substituted cycloalkylgroups.

The term “urethane” as used herein refers to a group of the generalformula:

The term “aryl” as used herein refers to monocyclic, fused bicyclic, andfused tricyclic carbocyclic aromatic ring systems including, but notlimited to, phenyl, naphthyl, tetrahydronaphthyl, phenanthrenyl,biphenylenyl, indanyl, indenyl, anthracenyl, and fluorenyl.

The term “heteroaryl” as used herein refers to monocyclic, fusedbicyclic, and fused tricyclic aromatic ring systems, wherein one tofour-ring atoms are selected from the group consisting of oxygen,nitrogen, and sulfur, and the remaining ring atoms are carbon, said ringsystem being joined to the remainder of the molecule by any of the ringatoms. Nonlimiting examples of heteroaryl groups include, but are notlimited to, pyridyl, pyrazinyl, pyrimidinyl, pyrrolyl, pyrazolyl,imidazolyl, thiazolyl, tetrazolyl, oxazolyl, isooxazolyl, thiadiazolyl,oxadiazolyl, furanyl, quinolinyl, isoquinolinyl, benzoxazolyl,benzimidazolyl, and benzothiazolyl.

The term “heterocycloalkyl” as used herein refers to an aliphatic,partially unsaturated or fully saturated, 2- to 14-membered ring system,including single rings of 3 to 8 atoms and bi- and tricyclic ringsystems. The heterocycloalkyl ring systems include one to fourheteroatoms independently selected from oxygen, nitrogen, and sulfur,wherein a nitrogen and sulfur heteroatom optionally can be oxidized anda nitrogen heteroatom optionally can be substituted. Representativeheterocycloalkyl groups include, but are not limited to, pyrrolidinyl,pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, triazine,benzotriazine, piperidinyl, piperazinyl, oxazolidinyl, isoxazolidinyl,morpholinyl, thiazolidinyl, isothiazolidinyl, and tetrahydrofuryl.

The terms “substituted aryl,” “substituted heteroaryl,” and “substitutedheterocycloalkyl” as used herein refer to an aryl, heteroaryl, orheterocycloalkyl group substituted by a replacement of one, two, orthree of the hydrogen atoms thereon with a substitute selected from thegroup consisting of C₃-C₈ cycloalkyl, hydroxyalkyl, substitutedcycloalkyl, ester, ether, aryl, heteroaryl, heterocycloalkyl,substituted aryl, substituted heteroaryl, substituted heterocycloalkyl,hydroxyl, halogen, cyano, amino, amide, imide, urethane, OR, N(R)₂,C(═O)N(R)₂, O(CH₂)₁₋₃N(R)₂, O(CH₂)₁₋₃CO₂H, and trifluoromethyl.

The term “amino” as used herein refers an —NH₂ or —NH— group, whereineach hydrogen in each formula can be replaced with an alkyl, cycloalkyl,aryl, heteroaryl, heterocycloalkyl, substituted alkyl, substitutedcycloalkyl, substituted aryl, substituted heteroaryl, or substitutedheterocycloalkyl group, i.e., N(R)₂. In the case of —NH₂, the hydrogenatoms also can be replaced with substituents taken together to form a 5-or 6-membered aromatic or non-aromatic ring, wherein one or two carbonsof the ring optionally are replaced with a heteroatom selected from thegroup consisting of sulfur, oxygen, and nitrogen. The ring alsooptionally can be substituted with an alkyl group. Examples of ringsformed by substituents taken together with the nitrogen atom includemorpholinyl, phenylpiperazinyl, imidazolyl, pyrrolidinyl,(N-methyl)piperazinyl, and piperidinyl.

The term “hydroxyalkyl” as used herein refers to one or more of ahydroxy group attached as a substituent to a C₁-C₃₀ alkyl group.

The term “substituted hydroxyalkyl” as used herein refers to anhydroxyalkyl group that is substituted with one or more of C₃-C₈cycloalkyl, hydroxyalkyl, substituted cycloalkyl, ester, ether, aryl,heteroaryl, heterocycloalkyl, substituted aryl, substituted heteroaryl,substituted heterocycloalkyl, alkoxy, halogen, cyano, amide, imide,urethane, and amino.

The term “ether” as used herein refers to a C₁-C₅₀ alkyl group thatincludes one or more of an oxygen atom inserted within the alkyl group.For example, a diethyl ether (—CH₂CH₂CH₂CH₃) substituent is a C₄ ether.

The term “substituted ether” as used herein refers to an ether groupthat is substituted with one or more of C₃-C₈ cycloalkyl, hydroxyalkyl,substituted cycloalkyl, ester, ether, aryl, heteroaryl,heterocycloalkyl, substituted aryl, substituted heteroaryl, substitutedheterocycloalkyl, hydroxyl, halogen, cyano, amide, imide, urethane, andamino. For example, 1-ethoxyethanol (—CH₂CH₂OCH(OH)CH₃) is a C₄substituted ether, wherein a hydroxyl group is a substituent on theether.

The term “polyalkylglycol” as used herein refers to compounds of thegeneral structure of R¹(OR)_(n)OH, wherein R is selected from C₁-C₃₀alkyl groups and C₁-C₃₀ substituted alkyl groups, and R¹ is selectedfrom hydrogen, C₁-C₃₀ alkyl groups, C₁-C₃₀ substituted alkyl groups,C₃-C₈ cycloalkyl, hydroxyalkyl, substituted cycloalkyl, ester, ether,aryl, heteroaryl, heterocycloalkyl, substituted aryl, substitutedheteroaryl, substituted heterocycloalkyl, hydroxyl, halogen, cyano,amide, imide, urethane, and amino. For example, polyethylene glycol is apolyalkylglycol wherein R¹ is hydrogen and R is a C₂ alkyl group. Asanother example, polypropyleneglycol is a polyalkylglycol wherein R¹ ishydrogen and R is a C₃ alkyl group.

The term “halogen” as used herein refers to fluorine, chlorine, bromine,and iodine.

The term “cyano” as used herein refers to a —C≡N group, also designated—CN.

A sunscreen composition disclosed herein can include a variety ofphotoactive compounds, including one or more UV-A photoactive compoundsand one or more UV-B photoactive compounds. Preferably, a sunscreencomposition includes a photoactive compound selected from the groupconsisting of p-aminobenzoic acid and salts and derivatives thereof;anthranilate and derivatives thereof; dibenzoylmethane and derivativesthereof; salicylate and derivatives thereof; cinnamic acid andderivatives thereof; dihydroxycinnamic acid and derivatives thereof;camphor and salts and derivatives thereof; trihydroxycinnamic acid andderivatives thereof; dibenzalacetone naphtholsulfonate and salts andderivatives thereof; benzalacetophenone naphtholsulfonate and salts andderivatives thereof; dihydroxy-naphthoic acid and salts thereof;o-hydroxydiphenyldisulfonate and salts and derivatives thereof;p-hydroxydiphenyldisulfonate and salts and derivatives thereof; coumarinand derivatives thereof; diazole derivatives; quinine derivatives andsalts thereof; quinoline derivatives; hydroxy-substituted benzophenonederivatives; methoxy-substituted benzophenone derivatives; uric acidderivatives; vilouric acid derivatives; tannic acid and derivativesthereof; hydroquinone; benzophenone derivatives; 1,3,5-triazinederivatives, phenyldibenzimidazole tetrasulfonate and salts andderivatives thereof; terephthalylidene dicamphor sulfonic acid and saltsand derivatives thereof; methylene bis-benzotriazolyltetramethylbutylphenol and salts and derivatives thereof;bis-ethylhexyloxyphenol methoxyphenyl triazine and salts and derivativesthereof; diethylamino hydroxybenzoyl hexyl benzoate and salts andderivatives thereof; and combinations of the foregoing.

UV-A radiation (about 320 nm to about 400 nm), is recognized ascontributing to causing damage, to skin particularly to verylightly-colored or sensitive skin. A sunscreen composition disclosedherein preferably includes a UV-A photoactive compound. Preferably, asunscreen composition disclosed herein includes a dibenzoylmethanederivative UV-A photoactive compound. Preferred dibenzoylmethanederivatives include, 2-methyldibenzoylmethane; 4-methyldibenzoylmethane;4-isopropyldibenzoylmethane; 4-tert-butyldibenzoylmethane;2,4-dimethyldibenzoylmethane; 2,5-dimethyldibenzoylmethane;4,4′-diisopropyldibenzoylmethane; 4,4′-dimethoxydibenzoylmethane;4-tert-butyl-4′-methoxydibenzoylmethane;2-methyl-5-isopropyl-4′-methoxydibenzoylmethane;2-methyl-5-tert-butyl-4′-methoxydibenzoylmethane;2,4-dimethyl-4′-methoxydibenzoylmethane;2,6-dimethyl-4-tert-butyl-4′-methoxydibenzoylmethane, and combinationsthereof.

A preferred combination of photoactive compounds in a sunscreencomposition includes a UV-A and a UV-B photoactive compound. However,when 2-ethylhexyl-p-methoxycinnamate is included in a mixture with adibenzoylmethane derivative, the dibenzoylmethane derivative can becomeparticularly unstable. Without intending to be limited to any particularmechanism, it is believed that the cinnamate ester reacts with anexcited-state dibenzoylmethane derivative in a bimolecular pathway thatrenders both the dibenzoylmethane derivative and the cinnamate esterincapable of absorbing UV radiation. It has been found, quitesurprisingly, that the use of one or more of a derivative ofdiphenylmethylenemalonic acid and derivative of fluorene (includingderivatives of cyano(9H-fluoren-9-ylidene) acetic acid and diesters andpolyesters of 9H-fluoren-9-ylidenemalonic acid) increases the stabilityof a sunscreen composition that includes 2-ethylhexyl-p-methoxycinnamateand a dibenzoylmethane derivative. Thus, one embodiment of a sunscreencomposition includes 2-ethylhexyl-p-methoxycinnamate, a dibenzoylmethanederivative, and one or more of a derivative of diphenylmethylenemalonicacid and a derivative of fluorene (e.g., derivatives ofcyano(9H-fluoren-9-ylidene) acetic acid and diesters and polyesters of9H-fluoren-9-ylidenemalonic acid). Octofluorene is particularlypreferred.

One embodiment of a sunscreen composition disclosed herein includes amixture of a photoactive compound and a compound selected from the groupconsisting of compounds of formulae (I), (II), (IV) to (VI), andcombinations thereof:

wherein, R¹, R², R³, R⁴, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, and R¹² are the sameor different and are selected from the group consisting of C₁-C₃₀ alkyl,C₃-C₈ cycloalkyl, substituted alkyl, hydroxyalkyl, alkoxyalkyl,substituted cycloalkyl, ester, aryl, heteroaryl, heterocycloalkyl,substituted aryl, substituted heteroaryl, substituted heterocycloalkyl,cyano, and amino; C¹⁷, C¹⁸, C¹⁹, C²⁰, C²¹, C²², C²³, C²⁴, C²⁵, C²⁶, C²⁷,and C²⁸ are same or different and are selected from the group consistingof hydrogen, C₁-C₃₀ alkyl, C₃-C₈ cycloalkyl, substituted alkyl,hydroxyalkyl, alkoxyalkyl, substituted cycloalkyl, ester, aryl,heteroaryl, heterocycloalkyl, substituted aryl, substituted heteroaryl,substituted heterocycloalkyl, hydroxyl, alkoxy, halogen, cyano, andamino; q and r are each in the range of 0 to 100; and a, b, c, d, e, f,g, h, i, j, and l are each in the range of 0 to 4. Compounds of formula(I), (II), and (IV) to (VI) are able to stabilize one or morephotoactive compounds present in a sunscreen composition. Withoutintending to be limited to any particular mechanism of stabilization, itis believed that the photoactive compounds are stabilized bytransferring their excited state energy (e.g., singlet and tripletenergy) to a derivative of diphenylmethylenemalonic acid and/or aderivative of fluorene (i.e., a derivative ofcyano(9H-fluoren-9-ylidene) acetic acid and a diester and/or polyesterof 9H-fluoren-9-ylidenemalonic acid). It is believed that the transferof excited state energy takes place because it leads to the mostefficient dissipation of the excited state energy (e.g., through therapid isomerizations discussed above). Each of the R groups in acompound of formula (I) or a compound of formula (II) (R¹, R², R³ andR⁴) is preferably selected from C₁-C₁₅ branched chain alkyls.Preferably, each of the R groups in a compound of formula (I) or acompound of formula (II) (R¹, R², R³ and R⁴) is 2-ethylhexane.

It is preferred that a compound selected from the group consisting ofcompounds of formulae (I), (II), (IV) to (VI), and combinations thereof,is present in a sunscreen composition in a range of about 0.1% to about25% by weight of the total weight of the composition, more preferablyabout 0.1% to about 10%, still more preferably about 0.5% to about 5%.

Derivatives of fluorene, including derivatives ofcyano(9H-fluoren-9-ylidene) acetic acid and diesters ofdiphenylmethylenemalonic acid can be prepared by a Claisen-type(Claisen-Schmidt) condensation reaction. For example, octofluorene canbe prepared by reacting 2-ethylhexyl cyanoacetate with 9-fluorenone inthe presence of acetic acid and sodium acetate.

Another embodiment of the invention is a compound of formula (III),

wherein R⁵ is selected from the group consisting of C₃-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, substituted cycloalkyl, aryl, heteroaryl,heterocycloalkyl, substituted aryl, substituted heteroaryl, substitutedheterocycloalkyl, and amino; R²⁹ and R³⁰ are the same or different andare selected from the group consisting of hydrogen, C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, ester, aryl, heteroaryl, heterocycloalkyl,substituted aryl, substituted heteroaryl, substituted heterocycloalkyl,hydroxyl, alkoxy, halogen, cyano, imide, urethane, amide, and amino; andm and n are each in the range of 0 to 4. Preferably, R⁵ is selected fromC₃-C₂₀ branched chain alkyls, and C₁-C₃₀ hydroxyalkyls. More preferably,R⁵ is a C₂-C₈ hydroxyalkyl group. In particular, R⁵ preferably, isselected from the group consisting of ethanol, propan-1-ol, propan-2-ol,1-buatanol, methylpropan-1-ol, 2,2-dimethylpropan-1-ol, and2-methylpropan-2-ol.

Compounds of formula (III), quite surprisingly, are able to increase thestability of a photoactive compound in a sunscreen composition. Thus,preferably, a compound of formula (III) is present in a sunscreencomposition, for example, in a range of about 0.1% to about 25% byweight of the total weight of the composition, preferably in a range ofabout 0.1% to about 10%.

Moreover, compounds of formula (III), quite surprisingly, are intenselycolored and can be used as a pigment in a paint or other applicationwhere it would be advantageous to have a coloring component present inthe mixture, and would be expected to be a photostable pigment. Acompound of formula (III) can also have a dual purpose in an application(e.g., a paint composition) as photostabilizing one or more photoactivecompounds present in the application and to impart color to theapplication.

The compounds of formula (III), quite surprisingly, are able to impartcolor to a mixture of components. For example, the compound shown belowin formula (IX)[1-ethylhexyl cyano(9H-fluoren-9-ylidene)acetate], is abrightly yellow colored compound.

The color of such compounds can be controlled to reflect a particularwavelength of light, and thereby to appear to the visible eye aparticular color, by placing at least one substituent on the one of thetwo aromatic rings of the fluorene core structure (labeled above as ringA and A′). For example, when two nitro (NO₂) groups are substituted atthe 2 and 7 positions on the aromatic rings A and A′ in the structureshown in formula (IX), the compound appears green in color.

The compounds of formula (III) can be used in various applications as acolorant to impart a particular color to a composition, including usedas a colorant in coatings and inks. Preferably, when a compound offormula (III) is used as a colorant in inks, the compound is used as acolorant in a digital printing process. The use of compounds of formula(III) as a colorant provides the advantages that: (1) the compounds areextremely stable and will not degrade (lose its color) after they beingapplied on a substrate (e.g., paper); and (2) as described herein, thecompounds of formula (III) are able to increase the photostability ofthe composition by absorbing the excited state energy of the othercomponents in the composition and by absorbing UV-A light.

Thus, one embodiment of the inventions is a method of coloring anarticle, including adding to the article a compound of formula (III):

wherein R⁵ is selected from the group consisting of C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, substituted cycloalkyl, aryl, heteroaryl,heterocycloalkyl, substituted aryl, substituted heteroaryl, substitutedheterocycloalkyl, and amino; R²⁹ and R³⁰ are the same or different andare selected from the group consisting of hydrogen, C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, ester, aryl, heteroaryl, heterocycloalkyl,substituted aryl, substituted heteroaryl, substituted heterocycloalkyl,hydroxyl, alkoxy, halogen, cyano, imide, urethane, amide, and amino; andm and n are each in the range of 0 to 4. Preferably, R⁵ is selected fromthe group consisting of C₁-C₂₀ branched chain alkyls, and C₁-C₃₀hydroxyalkyls. More preferably, R⁵ is selected from C₂-C₈ hydroxyalkyls,and in particular, R⁵ is a selected from the group consisting ofethanol, propan-1-ol, propan-2-ol, 1-buatanol, methylpropan-1-ol,2,2-dimethylpropan-1-ol, and 2-methylpropan-2-ol.

The compounds of formula (III) can be used as a colorant in a liquid,solid and/or a semi-solid (e.g., a gel) article. Furthermore, thecompounds can be added to articles that include, for example, paints,inks (printing inks), films, and plastics. Preferably, the compounds offormula (III) are used as a colorant in an ink and, more preferably, asa colorant in a dry ink for use in a digital printer. When used in afilm article, such as a wrapping, the compound of formula (III) acts asa colorant and also protects the material that it covers from UVradiation. When used as a colorant, the compound of formula (III) can bedesigned to be soluble in a component of the article by the design ofsubstituents on the R⁵ group. For example, the R⁵ groups in the exampleshown above in formula (IX) (2-ethylhexyl) could optionally besubstituted with one or more hydroxy groups to enhance the compound'ssolubility in an aqueous media. Thus, the compounds of formula (III)provide a great deal of flexibility with regards to the compatibilitywith various articles. To use a compound of formula (III) as a colorant,the compound can be added to the article or if the article is a mixtureof components, the compound can be added to one of the components of themixture prior to forming the final mixture. For example, in the processof forming plastics by thermosetting, a compound of formula (III) can beadded to the plastic at various point in the thermosetting process andthe compound will be incorporated in the structure of the plastic.

Another aspect of the invention is a compound selected from the groupconsisting of compounds of formula (IV) to (VI), and combinationsthereof:

wherein, R⁶ and R⁷ are the same or different and are selected from thegroup consisting of C₃-C₃₀ alkyl, C₃-C₈ cycloalkyl, substituted alkyl,hydroxyalkyl, alkoxyalkyl, substituted cycloalkyl, ester, aryl,heteroaryl, heterocycloalkyl, substituted aryl, substituted heteroaryl,substituted heterocycloalkyl, cyano, and amino; R⁸, R⁹, R¹⁰, R¹¹, andR¹² are the same or different and are selected from the group consistingof C₁-C₃₀ alkyl, C₃-C₈ cycloalkyl, substituted alkyl, hydroxyalkyl,alkoxyalkyl, substituted cycloalkyl, ester, aryl, heteroaryl,heterocycloalkyl, substituted aryl, substituted heteroaryl, substitutedheterocycloalkyl, cyano, and amino; C²¹, C²², C²³, C²⁴, C²⁵, c²⁶, C²⁷,and C²⁸ are the same or different and are selected from the groupconsisting of hydrogen, C₁-C₃₀ alkyl, C₃-C₈ cycloalkyl, substitutedalkyl, hydroxyalkyl, alkoxyalkyl, substituted cycloalkyl, ester, aryl,heteroaryl, heterocycloalkyl, substituted aryl, substituted heteroaryl,substituted heterocycloalkyl, hydroxyl, alkoxy, halogen, cyano, andamino; q and r are each in the range of 0 to 100; and e, f, g, h, i, j,and l are each in the range of 0 to 4.

Polyesters of formula (V) and formula (VI) can be prepared by thetransesterification of a diester with a diol, for example as shown belowfor dimethyl isophthalate:

Transesterification can proceed to form a polymer under acidic, basic,or neutral conditions.

Compounds of formulae (IV) to (VI), quite surprisingly, are able toincrease the stability of a photoactive compound in a sunscreencomposition. Thus, preferably, one or more of a compound of formula(IV), a compound of formula (V), and a compound of formula (VI) ispresent in a sunscreen composition in a range of about 0.01% to about30% by weight of the total weight of the composition, more preferably ina range of about 0.1% to about 10%.

Compounds of formula (III), quite surprisingly, are able to increase thephotostability of a dibenzoylmethane derivative. Without intending to belimited to a particular mechanism, it is believed that a compound offormula (III) (e.g., octofluorene) stabilizes a dibenzoylmethanederivative by accepting the triplet energy of an excited statedibenzoylmethane derivative. This process of accepting the tripletexcited energy of a dibenzoylmethane derivative converts the excitedstate dibenzoylmethane derivative to a ground state dibenzoylmethanederivative and allows the ground state dibenzoylmethane derivative tofurther absorb UV radiation. Thus, another embodiment of the inventionis a method for photostabilizing a sunscreen composition including adibenzoylmethane derivative, the method including the step of adding tothe dibenzoylmethane derivative a photostabilizing amount of a compoundof formula (III):

wherein R⁵ is selected from the group consisting of C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, substituted cycloalkyl, aryl, heteroaryl,heterocycloalkyl, substituted aryl, substituted heteroaryl, substitutedheterocycloalkyl, and amino; R²⁹ and R³⁰ are the same or different andare selected from the group consisting of hydrogen, C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, ester, aryl, heteroaryl, heterocycloalkyl,substituted aryl, substituted heteroaryl, substituted heterocycloalkyl,hydroxyl, alkoxy, halogen, cyano, imide, urethane, amide, and amino; andm and n are each in the range of 0 to 4. Preferably, R⁵ is selected fromC₁-C₃₀ hydroxyalkyls. More preferably, R⁵ is selected from C₂-C₈hydroxyalkyls, and in particular, R⁵ is a selected from the groupconsisting of ethanol, propan-1-ol, propan-2-ol, 1-buatanol,methylpropan-1-ol, 2,2-dimethylpropan-1-ol, and 2-methylpropan-2-ol.

Likewise, compounds of formulae (IV) to (VI), quite surprisingly, areable to increase the photostability of a dibenzoylmethane derivative.Without intending to be limited to a particular mechanism, it isbelieved that a compound selected from the group consisting of compoundsof formulae (IV) to (VI) is able to photostabilize a dibenzoylmethanederivative by accepting the triplet excited energy from an exciteddibenzoylmethane derivative. Thus, another embodiment of the inventionis a method for photostabilizing a dibenzoylmethane derivative, themethod including the step of adding to the dibenzoylmethane derivative aphotostabilizing amount of a compound selected from the group consistingof compounds of formulae (IV) to (VI), and combinations thereof:

wherein, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, and R¹² are the same or different andare selected from the group consisting of C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, alkoxyalkyl, substitutedcycloalkyl, ester, aryl, heteroaryl, heterocycloalkyl, substituted aryl,substituted heteroaryl, substituted heterocycloalkyl, cyano, and amino;C²¹, C²², C²³, C²⁴, C²⁵, C²⁶, C²⁷, and C²⁸ are the same or different andare selected from the group consisting of hydrogen, C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, alkoxyalkyl, substitutedcycloalkyl, ester, aryl, heteroaryl, heterocycloalkyl, substituted aryl,substituted heteroaryl, substituted heterocycloalkyl, hydroxyl, alkoxy,halogen, cyano, and amino; q and r are each in the range of 0 to 100;and e, f, g, h, i, j, and l are each in the range of 0 to 4. Preferably,in a compound of formula (IV) R⁶ and R⁷ are the same and are selectedfrom C₃-C₂₀ branch chain alkyls. More preferably, in a compound offormula (IV) R⁶ and R⁷ are the same and are 2-ethylhexane.

A compound selected from the group consisting of compounds of formulae(IV) to (VI), and combinations thereof, preferably is present in asunscreen composition that includes a dibenzoylmethane derivative in arange of about 0.01% to about 30% by weight of the total weight of thecomposition, more preferably about 0.1% to about 10%, and still morepreferably about 0.5% to about 5%. Compounds of formulae (IV) to (VI),quite surprisingly, are able also to act as a photoactive compound byabsorbing UV radiation. Thus, is addition to photostabilizing aphotoactive compound, compounds of formulae (IV) to (VI) can protecthuman skin from the harmful effects of UV radiation.

Compounds of formula (XI), quite surprisingly, are able also to act as aphotoactive compound by absorbing UV radiation at a peak wavelength ofabsorbance at 325-350 nm. FIG. 1 shows the absorbance spectra foroctofluorene (a compound of formula (XI), wherein R⁵ is 2-ethylhexane).Accordingly, another embodiment of the invention is a method ofprotecting human skin from ultraviolet radiation comprising topicallyapplying to the skin, in a cosmetically acceptable carrier, a compoundof formula (XI):

wherein R⁵ is selected from the group consisting of C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, substituted cycloalkyl, aryl, heteroaryl,heterocycloalkyl, substituted aryl, substituted heteroaryl, substitutedheterocycloalkyl, and amino; R²⁹ and R³⁰ are the same or different andare selected from the group consisting of hydrogen, C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, ester, aryl, heteroaryl, heterocycloalkyl,substituted aryl, substituted heteroaryl, substituted heterocycloalkyl,hydroxyl, alkoxy, halogen, cyano, imide, urethane, amide, and amino; andm and n are each in the range of 0 to 4.

Polyesters, for example, can be prepared by the transesterification of adiester with a diol or by the esterification of a diacid with a diol,for example as shown below in formula (X) for dimethyl(diphenylmethylene)malonate:

Transesterification can proceed to form a polymer under acidic, basic,or neutral conditions. When a polymer is prepared as shown above informula (X), the polymerization can be terminated with the addition of acompound, such as a alcohol, that cannot react any further to elongatethe polymer chain. It has been found, quite surprisingly, that acompound of formula (III) can be used to terminate a polymerizationreaction. It has been found that one or more of a compound of formula(III) can be used to terminate polymerizations of polyesters,polyamides, polyolefins, and polyurethanes, for example. Thus, anotheraspect of the invention is a method of making a polymer, includingterminating a polymer chain with a compound selected from the groupconsisting of compounds of formula (III):

wherein R⁵ is selected from the group consisting of C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, substituted cycloalkyl, aryl, heteroaryl,heterocycloalkyl, substituted aryl, substituted heteroaryl, substitutedheterocycloalkyl, and amino; R²⁹ and R³⁰ are the same or different andare selected from the group consisting of hydrogen, C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, ester, aryl, heteroaryl, heterocycloalkyl,substituted aryl, substituted heteroaryl, substituted heterocycloalkyl,hydroxyl, alkoxy, halogen, cyano, imide, urethane, amide, and amino; andm and n are each in the range of 0 to 4. Preferably, the polymer chainis selected from the group consisting of polyesters, polyamides,polyolefins, polyurethanes, and combinations thereof. For example, acompound of formula (III) can be incorporated into a synthetic plastic,such as polystyrene, as a terminator in the plasticization process; andby terminating the polymer, the compound becomes part of the plastic andalso terminates the plasticization process. It has been found thatpolymers formed according to this method can be used to photostabilize aphotoactive compound in a sunscreen composition.

EXAMPLES

The following examples are provided to illustrate the invention but arenot intended to limit the scope of the invention.

Example 1

Octofluorene was prepared by placing 9-fluorenone (130.0 g, 0.721 mole,1.0 mole equivalence), 2-ethylhexyl cyanoacetate (143.7 g, 0.728 mole,1.01 eq), ammonium acetate (5.0 g, 0.065 mole, 0.09 eq), toluene (450ml), and acetic acid (90 ml) into a 1 liter 3-neck round bottom flask(the reaction flask). The reaction flask was assembled with mechanicalstirrer, condenser, Dean-Stark receiver, thermometer, and nitrogeninlet. The reaction mixture was then heated to reflux and water wasremoved continuously. The water phase (29 ml; expected water fromreaction was 13 ml) was removed and the reaction was refluxed for 18 h.When gas chromatography (GC) showed complete consumption of one of thereagents, the reaction mixture was cooled to room temperature, washedwith water (2×400 ml), diluted sodium bicarbonate (400 ml), and water(300 ml). All water washings were discarded and the organic phase wasplaced back in the reaction flask and all solvents were removed bydistillation under vacuum. Traces of toluene were removed by steamdistillation. The desired product, octofluorene, (270 g, 96% pure asdetermined by GC) was dried, and filtered over CELITE filter medium.

Example 2

A series of sunscreen compositions was prepared by mixing theingredients and concentrations (formulations) shown in Table II below:

TABLE II 4% 4% Ingredients Octocrylene Octofluorene Oil Phase Avobenzone2.00% 2.00% Octyl salicylate 5.00% 5.00% Octyl-p-methoxy Cinnamate 7.50%7.50% Octofluorene 3.60% Octocrylene 3.60% C₁₂-C₁₅ alkyl benzoates10.00% 10.00% Bodying Agent And Film-Former Stearyl alcohol 1.00% 1.00%C₃₀-C₃₈ olefin/Isopropyl maleate/MA 2.00% 2.00% copolymer EmulsifiersSteareth 21 0.32% 0.25% Steareth 2 0.30% 0.25% Polyglyceryl-3 methylglucose distearate 3.00% 3.00% Water Phase Disodium EDTA 0.05% 0.05%Glycerin 3.00% 3.00% Methylpropanediol 2.00% 2.00% Phenoxyethanol &parabens 0.60% 0.60% Stabilizer and Neutralizer Carbomer 0.20% 0.20%Sodium hydroxide (25% solution) 0.32% 0.32% Water 59.11% 59.23%

Oil-in-water emulsions were created, wherein the aqueous phase was madeup of water, the water phase ingredients, the stabilizer andneutralizer, the emulsifiers, and the bodying agent and film-formerlisted above. The resulting sunscreens were tested for photostability bymeasuring absorbance on a Labsphere UV-1000S Ultraviolet TransmittanceAnalyzer (software version 1.27) before and after irradiation with aSolar Light Company model 16S solar simulator (equipped with a WG 320filter to transmit radiation greater than 290 nm) in 5 MED increments upto 30 MED. Output was monitored by a PMA 2105 UV-B DCS Detector(biologically weighted) and controlled by a PMA 2100 Automatic DoseController (Solar Light Co.).

To test stability, a slide was positioned on the UV transmittanceanalyzer using registration marks, and a scan of a 1 cm spot on theslide was performed. The slide was then transferred to a holder placedadjacent to the solar simulator and, using a calipers, was positionedsuch that the beam of UV radiation exiting the solar simulatorilluminated the same 1 cm spot on the slide. The following softwaresettings were used: UV-B=290-320 nm; UV-A=320-400 nm. Following anexposure of 5 MED, the slide was again placed in position on the UVtransmittance analyzer, and a scan of the exposed spot was performed.The procedure was repeated on the same 1 cm spot on the slide until thedesired total radiation dosage was achieved.

FIG. 3 is a graph of the percent absorbance of the sunscreencompositions listed in Table II at various intervals of exposure toradiation. As shown in FIG. 3, a composition including 4% octofluoreneis more photostable than a composition including 4% octocrylene (after35 MED exposure to UV radiation at a wavelength of 370 nm).

Example 4

A series of sunscreen compositions were prepared by mixing theingredients and concentrations (formulations) shown in Table III below:

TABLE III Ingredients 4% OF 4% OC 2% OF 1% OF Control Oil PhaseAvobenzone 2.00% 2.00% 2.00% 2.00% 2.00% Octyl methoxycinnamate 4.00%4.00% 4.00% 4.00% 4.00% Octofluorene 4.00% 2.00% 1.00% Octocrylene 4.00%C₁₂-C₁₅ alkyl benzoates 10.00% 10.00% 12.00% 13.00% 14.00% Avobenzone2.00% 2.00% 2.00% 2.00% 2.00% Octyl methoxycinnamate 4.00% 4.00% 4.00%4.00% 4.00% Bodying Agent And Film-Former Stearyl alcohol 1.00% 1.00%1.00% 1.00% 1.00% C₃₀-C₃₈ olefin/Isopropyl 2.00% 2.00% 2.00% 2.00% 2.00%maleate/MA copolymer Emulsifiers Steareth 21 0.30% 0.31% 0.31% 0.32%0.32% Steareth 2 0.20% 0.19% 0.19% 0.18% 0.18% Polyglyceryl-3 methyl3.00% 3.00% 3.00% 3.00% 3.00% glucose distearate Water Phase DisodiumEDTA 0.05% 0.05% 0.05% 0.05% 0.05% Glycerin 3.00% 3.00% 3.00% 3.00%3.00% Methylpropanediol 2.00% 2.00% 2.00% 2.00% 2.00% Phenoxyethanol &0.60% 0.60% 0.60% 0.60% 0.60% parabens Stabilizer and NeutralizerCarbomer 0.20% 0.20% 0.20% 0.20% 0.20% Sodium hydroxide (25% 0.28% 0.28%0.28% 0.28% 0.28% solution) Water 67.37% 67.37% 67.37% 67.37% 67.37%

Oil-in-water emulsions were created and the stabilities of thecompositions of this example were tested according to the proceduresdescribed above in Example 2.

FIG. 4 is a graph of the percent absorbance of the sunscreencompositions listed in Table III at various intervals of exposure toradiation. FIG. 4 shows the photostability of sunscreen compositionsincluding various levels octocrylene and/or octofluorene. In particular,the absorbance of the sunscreen compositions at a wavelength of 310 nmwas measured, which is the approximate peak absorbance foroctyl-p-methoxy cinnamate; thus, photostability data shown in FIG. 4primarily represent the photostability of the UV-B photoactive compound,octyl-p-methoxy cinnamate. As discussed above, when a dibenzoylmethanederivative is combined in a sunscreen composition includingoctyl-p-methoxy cinnamate, the dibenzoylmethane derivative becomesparticularly unstable. However, as shown in FIG. 4, a stable sunscreencomposition was formed in a composition including 4% octofluorene.

Example 5

A series of sunscreen compositions were prepared by mixing theingredients and concentrations (formulations) shown in Table IV below:

TABLE IV Neg. Ingredients 4% OF 4% OC 2% OF 1% OF Control Oil PhaseAvobenzone 2.00% 2.00% 2.00% 2.00% 2.00% Octyl-p-methoxy 4.00% 4.00%4.00% 4.00% 4.00% Cinnamate Octofluorene 4.00% 2.00% 1.00% Octocrylene4.00% C₁₂-C₁₅ alkyl benzoates 10.00% 10.00% 12.00% 13.00% 14.00% BodyingAgent And Film-Former Stearyl alcohol 1.00% 1.00% 1.00% 1.00% 1.00%C30-38 olefin/Isopropyl 2.00% 2.00% 2.00% 2.00% 2.00% maleate/MAcopolymer Emulsifiers Steareth 21 0.32% 0.32% 0.70% 0.70% 0.70% Steareth2 0.18% 0.18% 0.40% 0.40% 0.40% Polyglyceryl-3 methyl 3.00% 3.00% 3.00%3.00% 3.00% glucose distearate Water Phase Disodium EDTA 0.05% 0.05%0.05% 0.05% 0.05% Glycerin 3.00% 3.00% 3.00% 3.00% 3.00%Methylpropanediol 2.00% 2.00% 2.00% 2.00% 2.00% Phenoxyethanol & 0.60%0.60% 0.60% 0.60% 0.60% parabens Stabilizer and Neutralizer Carbomer0.20% 0.20% 0.20% 0.20% 0.20% Sodium hydroxide (25% 0.28% 0.28% 0.28%0.28% 0.28% solution) Water 66.37% 66.37% 59.77% 59.77% 64.77%

Oil-in-water emulsions were created and the stabilities of thecompositions of this example were tested according to the proceduresdescribed above in Example 2. FIG. 5 is a graph of the percentabsorbance of the sunscreen compositions listed in Table IV at variousintervals of exposure to radiation.

Example 6

A series of sunscreen compositions were prepared by mixing theingredients and concentrations (formulations) shown in Table V below:

TABLE V 5% DEHN, 5% Ingredients 0.45% OF 4% OC DEHN Control Oil PhaseAvobenzone 2.00% 2.00% 2.00% 2.00% Octyl salicylate 5.00% 5.00% 5.00%5.00% Diethylhexyl 2,6-naphthalate 5.00% 5.00% Octofluorene 0.45%Octocrylene 4.00% C₁₂-C₁₅ alkyl benzoates 10.00% 10.00% 10.00%Octyldodecyl neopentanoate 5.00% Polyisobutene 5.00% Diethylhexyl malate9.55% Bodying Agent And Film-Former Stearyl alcohol 1.00% 1.00% 1.00%1.00% C₃₀-C₃₈ olefin/ 2.00% 2.00% 2.00% 2.00% Isopropyl maleate/MAcopolymer Emulsifiers Steareth 21 0.32% 0.32% 0.70% 0.70% Steareth 20.18% 0.18% 0.40% 0.40% Polyglyceryl-3 methyl glucose 3.00% 3.00% 3.00%3.00% distearate Water Phase Disodium EDTA 0.05% 0.05% 0.05% 0.05%Glycerin 3.00% 3.00% 3.00% 3.00% Methylpropanediol 2.00% 2.00% 2.00%2.00% Phenoxyethanol & parabens 0.60% 0.60% 0.60% 0.60% Stabilizer andNeutralizer Carbomer 0.20% 0.20% 0.20% 0.20% Sodium hydroxide 0.28%0.28% 0.28% 0.28% (25% solution) Water 65.37% 66.37% 59.77% 64.77%

Oil-in-water emulsions were created and the stabilities of thecompositions of this example were tested according to the proceduresdescribed above in Example 2.

FIG. 6 is a graph of the percent absorbance of the sunscreencompositions listed in Table V at various intervals of exposure toradiation. This figure shows the increase in stability of absorbance at370 nm by the addition of very low levels of octofluorene to acomposition including avobenzone and 5% by weight of diethylhexylnaphthalate (DEHN).

Without intending to be limited to a particular mechanism of action, itis believed that in a composition including a diester or polyester ofnaphthalene dicarboxylic acid compound such as DEHN and a derivative offluorene, depending on the concentrations of the derivative of fluorene,one of the compounds would exclusively dominate the photostabilityprofile. Thus, one would expect that at high concentration of a diesteror polyester of naphthalene dicarboxylic acid compound, the addition oflow and very low levels of one or more derivatives of fluorene would notincrease the overall photostability of the dibenzoylmethane derivative.

It has been found, quite surprisingly however, that at low (e.g., 1% byweight) and very low levels (e.g., less that 0.5% by weight) of aderivative of fluorene, the combination can work synergistically toprovide even greater stabilization of a dibenzoylmethane derivative thanwould be expected. Without intending to be limited to any particularmechanism of operation, it is believed that the relatively highconcentration of diester or polyester of naphthalene dicarboxylic acidprovides a sufficient amount of the diesters or polyesters in proximityto dibenzoylmethane derivatives and, as the dibenzoylmethane derivativesare excited to their triplet excited states, the diester or polyesteraccepts the triplet excited energy at a sufficient rate to substantiallyreduce or prevent degradation of the dibenzoylmethane derivative.

At the same time, however, the relatively low amount of a derivative offluorene is believed to rapidly accept triplet excited energy from therelatively numerous diester or polyester molecules around it insolution, and very rapidly dissipate the energy through a rapidisomerization mechanism, thus generating ground state diesters orpolyesters of naphthalene dicarboxylic acid that are once again able toaccept excited state energy from an excited dibenzoylmethane derivative.Thus, the weight ratio of dibenzoylmethane derivative to a derivative offluorene is, preferably, at least about 6:1, for example at least 10:1.

In addition, as shown in FIG. 6, a stable composition was formed in acomposition including low levels of octofluorene and 5% by weight ofDEHN.

Example 7

A series of sunscreen compositions were prepared by mixing theingredients and concentrations (formulations) shown in Table VI below:

TABLE VI 5% 5% DEHN, DEHN, 5% D.C. 0.45% 0.45% DEHN AdjustmentIngredients OF 4% OC OC Alone Alone Control Oil Phase Avobenzone 2.00%2.00% 2.00% 2.00% 2.00% 2.00% Octyl salicylate 5.00% 5.00% 5.00% 5.00%5.00% 5.00% Diethylhexyl 2,6-naphthalate 5.00% 5.00% 5.00% Octofluorene0.45% Octocrylene 4.00% 0.45% C₁₂-C₁₅ alkyl benzoates 10.00% 10.00%10.00% Octyldodecyl neopentanoate 5.00% Polyisobutene 5.00% Diethylhexylmalate 9.55% 9.55% 10.00% Butyloctyl dimer with HDI 5.00% Bodying AgentAnd Film- Former Stearyl alcohol 1.00% 1.00% 1.50% 1.00% 1.20% 1.00%C₃₀-C₃₈ olefin/Isopropyl 2.00% 2.00% 2.00% 2.00% 2.00% 2.00% maleate/MAcopolymer Emulsifiers Steareth 21 0.32% 0.32% 0.33% 0.70% 0.55% 0.70%Steareth 2 0.18% 0.18% 0.18% 0.40% 0.7% 0.40% Polyglyceryl-3 methyl3.00% 3.00% 3.00% 3.00% 3.00% 3.00% glucose distearate Water PhaseDisodium EDTA 0.05% 0.05% 0.50% 0.05% 5.00% 0.05% Glycerin 3.00% 3.00%3.00% 3.00% 3.00% 3.00% Methylpropanediol 2.00% 2.00% 2.00% 2.00% 2.00%2.00% Phenoxyethanol & parabens 0.60% 0.60% 0.60% 0.60% 0.60% 0.60%Stabilizer and Neutralizer Carbomer 0.20% 0.20% 0.20% 0.20% 0.20% 0.20%Sodium hydroxide (25% 0.28% 0.28% 0.29% 0.28% 0.28% 0.28% solution)Water 65.37% 66.37% 64.40% 59.77% 59.47% 64.77%

Oil-in-water emulsions were created and the stabilities of thecompositions of this example were tested according to the proceduresdescribed above in Example 2.

FIG. 7 is a graph of the percent absorbance of the sunscreencompositions including various combinations of octocrylene,octofluorene, and DEHN as listed in Table VI and at various intervals ofexposure to radiation. As described in Example 6, it has been found,quite surprisingly, that at low (e.g., 1% by weight) and very low levels(e.g., less that 0.5% by weight) of a derivative of fluorene, thecombination works synergistically to provide even greater stabilizationof a dibenzoylmethane derivative than would be expected. As shown inFIG. 7, a stable sunscreen composition was formed by the combination of5% DEHN and 0.45% of octofluorene into a sunscreen composition.

Example 8

A series of sunscreen compositions were prepared by mixing theingredients and concentrations (formulations) shown in Table VII below:

TABLE VII 1% 2% 3% Ingredients DPFM DPFM DPFM Control Oil phaseAvobenzone 2.00% 2.00% 2.00% 2.00% Octyl salicylate 5.00% 5.00% 5.00%5.00% Diisopropyl fluorenmalonate 1.00% 2.00% 3.00% C₁₂-C₁₅ alkylbenzoates 14.00% 13.00% 12.00% 10.00% Polyisobutene 5.00% Dimethylcapramide 1.00% Bodying Agent And Film-Former Stearyl alcohol 1.00%1.00% 1.00% 1.00% C₃₀-C₃₈ olefin/Isopropyl 2.00% 2.00% 2.00% 2.00%maleate/MA copolymer Emulsifiers Steareth 21 0.38% 0.28% 0.28% 0.70%Steareth 2 0.18% 0.22% 0.22% 0.40% Polyglyceryl-3 methyl glucose 3.00%3.00% 3.00% 3.00% distearate Water Phase Disodium EDTA 0.05% 0.05% 0.05%0.05% Glycerin 3.00% 3.00% 3.00% 3.00% Methylpropanediol 2.00% 2.00%2.00% 2.00% Phenoxyethanol & parabens 0.60% 0.60% 0.60% 0.60% Stabilizerand Neutralizer Carbomer 0.20% 0.20% 0.20% 0.20% Sodium hydroxide (25%solution) 0.28% 0.28% 0.28% 0.28% Water 65.31% 65.37% 64.37% 64.77%

Oil-in-water emulsions were created and the stabilities of thecompositions of this example were tested according to the proceduresdescribed above in Example 2.

FIG. 8 is a graph of the percent absorbance of the sunscreencompositions listed in Table VII at various intervals of exposure toradiation. FIG. 8 shows the photostability of sunscreen compositionsincluding various levels of diiusopropyl fluorenmalonate (diisopropyl9H-fluoren-9-ylidenemalonate, a compound of formula IV wherein R⁶, R⁷are the same and are isopropane). As shown in FIG. 8, as the amount ofdiisopropyl fluorenmalonate is increased, the photostability of thephotoactive compounds in the composition (e.g., avobenzone) increases.

The foregoing description is given for clearness of understanding only,and no unnecessary limitations should be understood therefrom, asmodifications within the scope of the invention may be apparent to thosehaving ordinary skill in the art.

1. A compound of formula (III),

wherein R⁵ is selected from the group consisting of C₃-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, substituted cyoloalkyl, aryl, substitutedaryl, and amino; R²⁹ and R³⁰ are the same or different and are selectedfrom the group consisting of hydrogen, C₁-C₃₀ alkyl, C₃-C₈ cycloalkyl,substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl, ether,substituted ether, hydroxyl, alkoxy, halogen, cyano, imide, urethane,amide, and amino; and m and n are each in the range of 0 to
 4. 2. Thecompound of claim 1, wherein R⁵ is selected from C₃-C₂₀ branched chainalkyls.
 3. The compound of claim 1, wherein R⁵ is selected from C₁-C₃₀hydroxyalkyls.
 4. The compound of claim 3, wherein R⁵ is selected fromC₂-C₈ hydroxyalkyls.
 5. The compound of claim 4, wherein the alkyl ofsaid C₂-C₈ hydroxyalkyls is selected from the group consisting ofCH₂CH₂, CH₂CH₂CH₂, CH₂CH₂CH₂CH₂, CH₂CH(CH₃)CH₂, and CH₂C(CH₃)₂CH₂.
 6. Amethod of protecting a surface from ultraviolet radiation compxisingtopically applying to said surface; in a cosmetically acceptablecarrier, a compound of formula (XI):

wherein R⁵ is selected from the group consisting of C₁-C₃₀ alkyl, C₃-C₈cycloalkyl, substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl,ether, substituted ether, substituted cycloalkyl, aryl, substitutedaxyl, and amino; R²⁹ and R³⁰ are the same or different and are selectedfrom the group consisting of hydrogen, C₁-C₃₀ alkyl, C₃-C₈ cycloalkyl,substituted alkyl, hydroxyalkyl, substituted hydroxyalkyl, ether,substituted ether, ester, aryl, substituted aryl, hydroxyl, alkoxy,halogen, cyano, imide, urethane, amide, and amino; andm and n are eachin the range of 0 to 4.